YES! You need studded tires. If you're fishtailing, you're out of control and could land under a car or in a ditch very fast. Don't ride without.
Studs make the going a bit heavier, and you need to keep your bike a little more upright, minimal leaning over in corners. But once you have the hang of it, you can ride up hills so icy people can't walk up them. Studded tires rock. And they last a long time if you just break them in carefully (no hard braking the first 50 km or so). And you don't have to deflate your tires to very low pressures either.
You also need a good bright light in front and a red blinky in back. I'm a big fan of the Magicshine lights, great value for money.
Winter riding is much less about badassery and much more about bundle-uppery. - malkin
1995 Kona Cinder Cone commuterFrankenbike/Selle Italia SLR Lady Gel Flow
2008 white Nakamura Summit Custom mtb/Terry Falcon X
2000 Schwinn Fastback Comp road bike/Specialized Jett